Walker Ted McGowan, 18, was walking towards the summit of Yr Aran, near Rhyd Ddu, when he saw the drama unfold.

He said: “The whole ordeal happened over there on the ridge. There was obviously a training exercise going on at the time; lots of helicopters buzzing around and everything but this certain helicopter was basically hovering over the ridge and then obviously some malfunction occurred . . . but then the propeller started to slow down and smoke started to pour out of the engine.

“Then after that five minutes later it caught fire and you could really see the orange stick out. Smoke was really going out across like that. I stayed around and watched the crew - I think six of them - all of them got out safely and were walking down. It was quite an ordeal.”

Rescue teams at Rhyd Ddu near where an RAF helicopter went up in flames (Photo: Robert Parry-Jones)

Emergency services were called at about 1.45pm to Yr Aran, a mountain peak on a ridge south of Snowdon. Walkers reported seeing 10ft-high flames.

An air ambulance was sent to the scene, along with a coastguard helicopter.